WASHINGTON (USATODAY.com)  President Bush's declining job approval ratings have been the subject of much talk and speculation in recent months.

Last week, he hit 39%, the lowest level of his presidency, in the USA TODAY/CNN/Gallup Poll.

If he were looking ahead to re-election, which he is not, the Washington grapevine would be rife with talk that he is a goner.

But since Bush cannot seek another term, the chatter has shifted to his fellow Republicans running in the 2006 congressional elections.

The conventional wisdom now making the rounds in political and media circles around town is that the Democrats, given Bush's troubles, and some missteps on the part of some key GOP leaders on Capitol Hill, have their best chance in a decade of winning back control of Congress.

Why are Bush and the Republicans seen to be in so much trouble? Several factors:

• The messiness of the war in Iraq.

• High gasoline prices.

• An inadequate federal response to Hurricane Katrina.

• The indictment on campaign finance violations of former House Majority Leader Tom DeLay, and financial and ethics charges swirling around other Republican congressional leaders.

• The possibility of indictment of top White House aides in the leaking of the identity of a CIA operative Valerie Plame in connection with the dispute over whether Iraq was building weapons of mass destruction.

• The split in conservative ranks over Bush's nomination of White House counsel Harriet Miers to the Supreme Court.

Taken together, they are key ingredients of a recipe for political disaster next year.

But the 2006 elections are still one year away. And to revive an old expression that contains a kernel of truth — a year in politics can be a lifetime. So Bush and the Republicans still have time to set things right again. It will not be easy, however.

If we take a closer look at the USA TODAY poll, which recorded the president's job approval at 39%, we find that he is being saved from falling lower by his strong support among Republicans.

Overall, 84% of Republicans, even with all his problems, approve of the job Bush is doing. Compare that with 32% approval among independents and 8% among Democrats.

Bush cannot fall much lower with Democrats. They obviously find little there to approve of and are unlikely to experience a change of heart, barring some cataclysmic event.

Independents, a group that makes up about one-fifth of the electorate, are by their nature not heavily steeped in partisan politics. Therefore, their views are more fluid and can move up and down quickly depending on the news coming out of Washington.

A run of good news could raise Bush's ratings somewhat, but not that much because true independents are such a small group.

Thus, Bush has to hope that his solid Republican support doesn't erode. It could. The dispute among professional conservatives over Miers for the most part has not trickled down to the grass-roots level. If it does, GOP support for Bush could slip and his job approval fall to the mid-30s or lower — truly dangerous levels.

At that point, people begin talking about a failed presidency. He cannot afford that.

Bush is not alone among presidents with low approval levels. Since Gallup began measuring presidential job approval in the Franklin Roosevelt administration, seven of 10 have fallen lower than 39% at various times of their tenure: